The present invention relates to phacoemulsification and, more particularly, to a method and apparatus for control of phacoemulsification parameters in response to occluded and unoccluded conditions of a phacoemulsification handpiece.
Phacoemulsification techniques are well known in the field of ophthalmology going back to the late 1960's and the work of Dr. Charles Kelman. A full discussion of phacoemulsification is found in Chapter 11 "The Mechanics of Phacoemulsification; Chapter 12 "The Phacoemulsification Procedure"; Chapter 13, "Cataract Removal by Phacoemulsification" and Chapter 14 "Small Pupil Phacoemulsification Techniques" of The Surgical Rehabilitation of Vision--An Integrated Approach To Anterior Segment Surgery, edited by Lee T. Norman, W. Andrew Maxwell and James A. Davidson, Gower Medical Publishing, New York, N.Y., 1992, ISBN 0-397-44693-4. Chapters 11-14 thereof are incorporated herein by reference in their entirety.
Currently available phacoemulsification systems are manufactured and sold by Optical Micro Systems, Inc. of North Andover, Mass. under the trademarks "DIPLOMAT", "DIPLOMAT MMP", "OPSYS" and "OPSYS MMP". These systems have control units that include a variable speed peristaltic pump, a vacuum sensor, an adjustable source of ultrasonic power and a programmable microprocessor with operator selected presets for controlling aspiration rate, vacuum and ultrasonic power levels.
It is an object of the present invention to provide control over aspiration rates as a function of the occluded-unoccluded condition of the phacoemulsification handpiece.
It is another object of the present invention to provide control over ultrasonic power levels as a function of the occluded-unoccluded condition of the phacoemulsification handpiece.
It is a further object of the invention to provide variable pulse duty cycles for the ultrasonic power of a phacoemulsification system.